Relationship between Pain Intensity, Physical Factors, Pronociceptive Pain Modulation Profile and Psychological Vulnerability on Upper Limb Disability in Older Patients with Chronic Shoulder Pain

Background: Chronic shoulder pain is a very prevalent condition causing disability and functional impairment. The purpose of the study was to evaluate the relationship between pain intensity, physical variables, psychological vulnerability, pronociceptive pain modulation profile and disability in older people with chronic shoulder pain. Methods: A cross-sectional study was carried out. A total of 56 participants with non-specific chronic shoulder pain of the "Complejo Hospitalario Universitario" (Granada) and 56 healthy controls were included. The outcomes evaluated were pain intensity (visual analogue scale), physical factors (dynamometry for grip strength), psychological vulnerability (Fear-Avoidance Beliefs Questionnaire and Tampa Scale of Kinesiophobia), pronociceptive pain modulation profile (pain pressure algometry) and disability (Quick Disability Arm Shoulder Hand questionnaire). Results: Disability showed a positive correlation with pain and psychological vulnerability (p < 0.05) and a negative correlation with pronociceptive pain variables and dynamometry (p < 0.001). Psychological vulnerability also presented a strong negative correlation with proprioceptive pain variables and dynamometry and a positive correlation with pain (p < 0.05). In regard to the pronociceptive pain modulation profile, a strong negative correlation with pain (p < 0.001) and a positive moderate correlation with dynamometry (p < 0.001) were shown. Conclusions: Our results support a strong association between disability, psychological vulnerability and pronociceptive pain modulation profile in older adults with chronic shoulder pain.